Stadia target



E. A. DUDUIT STADIA TARGET Aug. 7, 1951 Filed Jan. 20, 1947 I 4; r HHIIIHHHHITFHH Patented Aug. 7, 1951 UNITED STATES PATENT OFFICE STADIA TARGET Eric A. Duduit, Portsmouth, Ohio Application January 20, 1947, Serial No. 723,165

1 Claim. 1

The present invention relates to improvements in surveying instruments, and more particularly to an improved stadia target attachment.

The primary object of the present invention is to provide a simple stadia target which is essentially an auxiliary target and which is so designed as to be easily attached to and used in conjunction with the standard englneers level rod.

The primary object of the present invention is to provide a stadia target, essentially an auxiliary target, which when used in connection with a standard surveyors or engineers level rod and a modified rod target, will enable an instrument man and rod man to determine profile, topography, contours or elevations necessary to land, highway, railroad, structural or other similar or related surveys.

A still further object of the invention is to provide a, clamping device for the auxiliary target which permits said target to be swung in a vertical are, thereby permitting quick adjustment thereof to the vertical angle of the transit. This easy and rapid adjustment permits the taking of direct slope readings, reduces the usual complex and tedious calculating to relative simple processes, and permits direct plotting without calculation.

The above and other objects of the invention will in part be obvious and will in part be hereinafter more fully pointed out.

Figure 1 is a front elevational view of the stadia target embodying the features of the present invention, the same being attached to a standard engineer's level rod;

Figure 2 is a top plan view thereof with the level rod being shown in section; and

Figure 3 is a diagrammatic view illustrating the manner of using the instrument.

Referring to the drawing for a more detailed description thereof, astandard engineers level rod is generally designated by the reference numeral 5, and as shown in Figure 2, the opposed sides of said rod are formed with vertically extending grooves 6. To the standard level rod 5, there is usually attached a target 1, with the rod usually spaced and supported substantially centrally thereof. While the present invention has been designed for use with the level rod 5 and target 1, the target I has been modified by cutting off the .portion to the right of the rod, as viewed in Figure 2 of the drawing. Therefore, it is to be understood that the level rod 5 and target 1 are merely shown for purposes of illustration and that the target attachment is capable of use with any desired type of rod.

l of the clamping screw i2 abuts.

The conventional target 1 is adjustably clamped to the rod 5 and is capable of vertical movement relative thereto. As shown in Figure 2 of the drawing, the rear face 9 of the target 1 carries a pair of spaced standards H] and [0a having aligned openings II for receiving the threaded clamping screw [2 having a milled or knurled head l3. The standard Ida has integrally formed therewith an L-shaped boss I5; the end [5 of which enters one of the grooves E. The target 7, standards It and Ida and L-shaped boss l5 are preferably cast as a unit.

The L-shaped boss [5 provides a backing for a leaf-spring 11- against which the threaded end As is to be understood, pressure of the clamping screw I2 on the leaf-spring ll forces the latter against the side of the level rod 5 to firmly retain the target in position thereon. When desiring to raise or lower the target 1, it is merely necessary to loosen the screw !2 to thereby free the target 1 for vertical movement on the rod. As soon as vertical adjustment of the target has been made, the screw 12 is again tightened. The spring 11 normally functions to sustain the weight of the target when not clamped, yet permits vertical adjustment against friction. The screw l2 merely clamps the spring l! against the rod when the desired position is located.

In accordance with the present invention, a standard engineers target 1 has been modified to include a portion l8 which extends at right angles to the front face of the standard target 1 and which is formed with a boss l9 adapted to ride in the other groove 6, or is directly opposed to the boss it. This portion [8 provides the means for carryin an auxiliary target, generally designated by the reference numeral 20, which target embodies the fundamental principles of the invention.

An auxiliary target 20 comprises a pair of spaced arms El and 22 which lie substantially parallel with the portion [8. The arms 2| and 22 are connected by a cross arm 23. The portion t8 and arms 2i and 22 are semi-circular, or curved, from their juncture with the cross arm 23. As more particularly shown in Figure 2 of the drawing, the arm 2| is shorter in length than the portion l8 which has a leg 3! extended around the edge of arm 2| to form an L-shaped' clamp. The front ends of the arms 2| and 22 are bent at right angles toward each other as indicated at 2A and 25 respectively.

The arms 2i and 22, together with the cross arm 23 provide a housing 26 for supporting a graduated target stick 21. The target stick 2] is secured in the housing 26 by means of a screw or the like 28, and said stick extends upwardly from the horizontal central line 29. If desired, the auxiliary target may include two sticks, such as the one designated by the reference numeral 21, with one above the center line and the other below the center line. This type of construction is preferred when using both upper and lower stadia wires of the surveying transit. However, from extensive field tests and actual use of the improved target, it has been found that a single stick extending upwardly from the horizontal line is all that is required. The stick 2'! may be of any desired length and may have any desired graduations thereon, but, as shown in the drawings, it is graduated to provide direct readings to .01 of a foot. Contrasting colors may be used to facilitate reading.

The auxiliary target 20 is pivotally connected to the portion l8 by means of a screw 30 which extends through the front endsof the portion I8 and arm 2|. By means thereof the auxiliary target 20 may be swung in a vertical are around the screw 30.

The outer extremity of the arm 2| is adjustably connected to the outer extremity of the portion i8 by means of the L-shaped clamp 3| and thumb screw 33. It will, therefore, be readily understood that upon loosening the thumb screw 33;,

the auxiliary target 20 will be free to move about the screw 30 relative to the portion IS. The clamp 3| is formed with a, finger 34 which acts as an index to indicate the angle on the arm 2| when said arm has been rotated about the screw 30.

The front face 32 of the arm 2| is formed with graduations which are calibrated to 60 each way from the horizontal. These graduations on the face of the arm 2| denote the angle at which the target has been swung. The finger or index 34 of the'clamp 3| will, of course, indicate the angle. To simplify setting the auxiliary target, a bead sight consisting of two projections 35 is cast integrally with the member 22. The bead sights are used when alignment of the target stick 2'! in a plane perpendicular to the line of sight of the transit is desired. They are intended for use up to a height of approximately feet on the level rod. For greater heights, the sights are not used, but the transit man indicates the proper angle setting at which the target is clamped. 'Angular adjustment of the auxiliary target is accomplished by loosening the thumb screw 33 and swinging the target about the center pivot 3|] until the line on the index 34 coincides with the proper angle on the calibrated face of the arm 2|, which may he graduated in units of degrees or otherwise, as desired.

There is illustrated in Figure 3 of the drawing the manner in which the present invention is used. The transit is set at 36 and the line of sight 38 directed toward the rod 5; some convenient angle relative to the horizontal 43 may be chosen by the instrument man operating the transit. Target 1 is set and clamped by screw l2 on line 38. Auxiliary target 20 is then rotated forward and clamped at angle 42 which is necessarily equal to angle 4|. This will bring stick It! at 90 degrees withline 3B, and since lines 38 and 39 diverge five-tenths of a foot for each hundred feet of distance 31, r one foot per hundred feet when lines 39 and 40 are used, it

will be evident that the distance 31 can be read directly or with slight mental deduction, while with the usual method when lines 38 and 39 are used with rod 5 only, the angularity of the reading on rod 5 necessitates the use of cumbersome stadia tables and calculation to correct for angularity. This is overcome in this invention by the stadia target stick 2'! being set at a right angle with line 38, which allows a direct reading.

Fig. 3 illustrates the use of the'device on an ascendinggrade, but it may be usedon a descending grade by reading the angle 4| below the horizontal and revolving auxiliary target 23 to the opposite side of vertical rod 5 and reading directly as before. i

In practice, this invention has saved the inventor up to per cent of field labor and costs, and has saved the draftsman equally as much by enabling him to plat line 38 on paper and drop a line from 29 equal to the target height on the rod, which locates the position of the foot of the rod directly without calculation. 1

Bead sights 35 as shown on Figs. 1 and 2 may also be used'to facilitate setting the target to the angle of the transit by sighting the line of the bead sights upon the transit, which automatically sets the auxiliary target to the proper angle.

This procedure is feasible up to eye level, and for all angles above eye level the instrument man instructs the rodman regarding the angle at which the target is to be set.

From the above description when taken in connection with the accompanying drawings, it will be readily apparent that there has been provided an auxiliary target which is simple in construction and which may be easily attached to and used in conjunction with the standard level rod, or the target modified as described hereinabove. The device is quickly and easily adjusted on the level rod and may be quickly and easily removed therefrom.- 7

It is obvious that many changes may be made in the details of construction without departing from the spirit of the invention as set forth in the appended claims.

I claim:

In combination with a level rod target having means for guiding saidtarget slidably along a level rod, a leg member secured to said target at right angles to the face thereof, an auxiliary target comprising a graduated stick and a stick holding member, a pivot means having its axis perpendicular to the direction of said guide means and parallel to said target face and securing said stick holding member on said leg member for pivotal adjustment about said axis, one of said members having an arcuate edge coaxial'with said pivot means, a scale along said arcuate edge and an index on said other of said members for indicating on said scale the angularity of said stick relative to the level rod, and a thumb screw engaging said members for fixing them in adjusted angular position.

ERIC A. DUDUIT.

REFERENCES CITED UNITED STATES PATENTS Name Date Classon Nov. 21, 1899 Number 

